1. Field of the Invention
This invention relates to the technical field of electronic modules, methods for manufacturing electronic modules, and electronic devices, in particular smart cards, comprising at least one electronic module. More specifically, the invention relates to secure electronic modules.
2. Description of the Related Art
In general, electronic modules are formed by a dielectric support film on which a metallised layer is laminated. On the side opposite the metallised layer, a microchip is glued and connected to different zones of the metallised layer.
In an electronic device, the electronic module is glued into a recess provided for that purpose in the body of the device.
That kind of electronic module finds application especially in smart cards.
Generally, in order to protect the microchip and its connections to the different zones of the metal layer, it is encapsulated by moulding protective resin on the electronic module. Such encapsulation is usually achieved with epoxy resin or epoxy mould compounds (EMCs), which are dark in colour. For their part, the card bodies in which the electronic modules are placed are generally made in light coloured plastic material, which makes it possible, by contrast, to see the electronic module through the card body.
In the field of top-quality smart cards, the fact that the electronic module is visible through the card is not acceptable from a marketing point of view. However, there are light-coloured EMCs, which would be invisible through the card; however, these are very costly and difficult to implement. That is because these EMCs tend to stick to the mould and the production line must be stopped frequently to clean the mould, thus increasing costs.
The problem of the visibility of the electronic module through the card body could also be avoided by applying a personalising coat on the back of the smart card, thus making the electronic module invisible. However, for certain types of secure card, the back of the card is coated with a transparent security coat on which no opaque coat is applied, in order precisely to keep the card secure.